The invention relates to a device for fine or finest processing of a rotationally symmetric work piece surface of a work piece, with a drive mechanism for driving the work piece around an axis of rotation, with two guidance mechanisms acting in radial directions with respect to the axis of rotation, and at least one tool acting in a radial direction, with a pressing mechanism for pressing the work piece against the drive mechanism, wherein the work piece can be disposed between the drive mechanism and the pressing mechanism as seen in the direction of the axis of rotation.
In the fine and finest processing of a rotationally symmetric work piece surface of a work piece, radial clamping poses the problem that rotationally symmetric work piece surfaces can be damaged by contact with the clamping tool. To prevent this, devices of the type stated above are used. On these devices, the work pieces are not clamped radially but axially. In this case, a work piece is fixed between a drive mechanism for driving the work piece around an axis of rotation and a pressing mechanism as seen in the direction of the axis of rotation. Positioning of the work piece in the radial direction is achieved using two guidance mechanisms.
A tool acting in the radial direction exerts a force on the work piece to be processed so that this may be displaced to the side with respect to the axis of rotation, that is, in the radial direction, unless additional measures are taken. To prevent this, it is possible, for example, to provide a third guidance mechanism so that the work piece is held between three guidance mechanisms in the radial direction. A further possibility is to provide only two guidance mechanisms, each at a different distance from the axis of rotation in the radial direction. With correct coordination of the different radial distances of the guidance mechanisms from the axis of rotation and the direction of rotation of the work piece, it is then also possible to prevent lateral displacement of the work piece by means of two guidance mechanisms. However, it is disadvantageous that, due to the offset between the axis of rotation of the drive mechanism and the real axis of rotation of the work piece, the latter moves in the radial direction relative to the drive mechanism and/or the pressing mechanism so that the end surfaces of the work piece rub against the corresponding facing surfaces of the drive mechanism and/or the pressing mechanism. This can damage the face-end surfaces of the work piece and/or the facing surfaces of the drive mechanism and/or the pressing mechanism. At the same time, stick-slip effects can occur with the consequence that the work piece cannot be processed with the necessary precision and, in particular, circular runout tolerances can no longer be complied with.
Based on the aforesaid considerations, the object of this invention is to create a device of the type stated above having the simplest possible structure that can process a work piece with low wear and high precision.